This section provides background information related to the present disclosure and is not necessarily prior art.
A significant amount (e.g., approximately one-third) of energy in fuel consumed by an internal combustion engine is lost as heat rejected through an exhaust system associated with the internal combustion engine. It is desirable to recover this heat or thermal energy from exhaust gas flowing through the exhaust system for various purposes. For example, such recovered thermal energy can be used to heat vehicle fluids to provide faster passenger cabin warm-up and windshield defrosting. Additionally or alternatively, the recovered thermal energy can be used to improve fuel economy by reducing friction and viscous losses in the vehicle lubrication systems, for example.